Aerodynamic Optimisation of a Camber Morphing 3-D Aerofoil in the Presence of Trailing Edge Flap Deflection

Abstract

Aircraft designed for a single flight condition perform poorly at other flight conditions. Camber-morphing aerofoils aim to achieve their camber change to potentially reduce this drag penalty. Morphing aircraft usually weigh more than their non-morphing counterparts, because of their increased mechanism and actuation weight complexity. A solution is sought here through combination of trailing edge flap deflection and optimization of remaining camber to reduce induced drag for a given flight design point. Such an arrangement is shown herein to require lesser camber morphing for optimal performance at off-design conditions. A new concept in aerofoil design is brought out in this way to reduce morphing effort. Minimum drag camber is developed through surface morphing while keeping the trailing edge flap (TEF) un-morphed. The objective function is formed through Lagrange multiplier. Principle of calculus of variations is applied to form matrix for solution. Flow is considered potential and compressible. Constant pressure singularities are used for lift representation. Induced drag component of the force is minimized subject to lift remaining same and the trailing edge flap camber and deflection remaining same. The optimal circulation determines the minimum drag, and the values of morphed camber. The program is executed on a 2.4 GHz laptop using gfortran compiler which is available in the fedora operating system. Fedora12 double precision 64bit is used for this work. Alternatively, Ubuntu operating system can also be utilized. Fedora and Ubuntu both are Linux platform based.